1. Field of the Invention
The present invention relates generally to an aseptic transfer bead for plastic containers, and more particularly to a transfer bead that provides the functionality of a standard transfer bead, as well as meeting the aseptic requirements that are applicable to the packaging of certain types of foods and beverages.
2. Description of the Related Technology
Transfer beads that are generally embodied as an annular projection extending from the neck or finish portion of a container are widely used in the packaging industry in order to provide a purchase location for certain types of conveying and handling equipment.
Certain types of beverages such as milk require sterile packaging. This can be accomplished by using the well-known hot fill process or through the use of aseptic packaging technology. The latter tends to be quite popular in Europe and is gaining popularity in other parts of the world as well. The aseptic packaging process is characterized by a sterilization procedure in which the container is sprayed or immersed in a sterilization fluid and then rinsed in a sterile environment before the product is injected into the container. In order to avoid contamination of the beverage that is being packaged, it is particularly important that the container be adequately rinsed after it has been exposed to the sterilization fluid.
Plastic containers for packaging beverages such as milk are typically formed using the extrusion blow molding process, in which the container is formed from a continuously extruded tube known as a parison that is periodically captured and inflated within a moving mold assembly, typically a mold wheel.
In order to form a transfer bead on the neck of a container that is being fabricated using such a process, it is necessary for the inner portion of the wall of the neck of the container to be bent outwardly in congruence with the shape of the intended annular projection of the transfer bead on the outer surface of the neck of the container. This creates a relatively thin, narrow annular passage that is in communication with the interior of the container neck. Unfortunately, the relative inaccessibility of this passage sometimes prevents the sterilization fluid from fully penetrating into the entire depth of the passage. Even when the sterilization fluid does manage to fully penetrate the passage, the sterilization fluid that is used in the aseptic packaging process tends to become trapped in this relatively inaccessible passage and is difficult to rinse out adequately enough to ensure that unwanted sterilization fluid does not end up in the packaged product.
It is clear that a need exists for an improved blow molded container that has a transfer bead for use of handling and that is also more suitable for use with the aseptic packaging process than were the conventional containers described above.